C2 Week 2 Programming Assignment Error

Week 2: Graded (programming) assignment error
When I run the cells with my code, it shows “All tests passed”.
But when I submit the assignment my grade is being shown as zero.
Not sure whether I modified (inserted/deleted few cells).
Kindly suggest how to start this assignment with a fresh notebook file (fresh file uploaded by the course team).

Thanks in advance,

There is a topic about that on the DLS FAQ Thread.

But note that a first step would be to show us what you see under “Show grader output” on the “My Submissions” page. It doesn’t always help, but sometimes there will be some useful clue about the nature of the error.

Also note that just as a general matter, passing the test cases in the notebook is just the first step and does not guarantee that you’ll pass the grader.

Thanks a lot for the superfast response. That really helped.